Fixed return value of ArgumentParser::find() for when the search string is not found, the correct value is now -1.

src/osg/ArgumentParser.cpp

@@ -230,7 +230,7 @@ int ArgumentParser::find(const std::string& str) const
             return pos;
         }
     }
-    return 0;
+    return -1;
 }
 
 bool ArgumentParser::match(int pos, const std::string& str) const

src/osg/DisplaySettings.cpp

@@ -401,7 +401,7 @@ void DisplaySettings::readCommandLine(ArgumentParser& arguments)
     }
 
     int pos;
-    while ((pos=arguments.find("--stereo"))!=0)
+    while ((pos=arguments.find("--stereo"))>0)
     {
         if (arguments.match(pos+1,"ANAGLYPHIC"))            { arguments.remove(pos,2); _stereo = true;_stereoMode = ANAGLYPHIC; }
         else if (arguments.match(pos+1,"QUAD_BUFFER"))      { arguments.remove(pos,2); _stereo = true;_stereoMode = QUAD_BUFFER; }